Name the source from which litmus solution is obtained. What is the use of this solution?

Explanation

**Step-by-Step Solution:**

1. **Identify the Source of Litmus Solution:**
- Litmus solution is obtained from a natural dye extracted from a lichen, specifically from a type of lichen known as *Rocella tinctoria*.

2. **Explain the Process of Obtaining Litmus Solution:**
- The natural dye from the lichen is extracted and then dissolved in distilled water to create the litmus solution.

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